A gas turbine engine consists basically of an air compression assembly that supplies a combustion chamber in which the air is mixed with a fuel to produce hot gases whose energy is recovered in a turbine assembly driving the compression means. The shafts connecting the various rotor bodies are supported in the statoric portions by bearings mounted in a pressurized enclosure. The enclosures make it possible to contain the oil that is injected onto the rolling bearings to ensure their lubrication and comprise sealing members, most frequently of the labyrinth type, that the containment air passes through. This air is laden with oil particles and in order to keep the oil consumption to as low a level as possible, it is a known practice to use deoiling equipment that separates the oil from the air that has flowed into the rolling bearing enclosures. In current engines, this equipment is incorporated either into the engine near the bearings themselves, or in the accessory gearbox, also called the AGB. The deoilers however are not 100% efficient. The exhausted air after it has passed through the deoilers still contains oil residues in the form of droplets that are ejected into the atmosphere. They are therefore the source of pollution and harm the environment.
The applicant has set itself the objective of reducing the polluting effect of the oil waste in the atmosphere.
According to the invention, the applicant has perfected a method for treating an airflow, laden with oil particles, flowing in a tube in communication with a rolling bearing enclosure of a gas turbine engine, wherein said airflow is made to travel into a coking box associated with a heating means, in which the air is heated to a sufficient temperature to coke the oil particles that it contains. Preferably, the solid residues produced by the coking are collected in the coking box.
Therefore the transformation by coking of the oil into gaseous and solid residues makes it possible to reduce the toxicity of the gases ejected into the atmosphere. On the one hand the coking makes it possible to reduce the volume of the oil waste, on the other hand, the residues are less toxic in themselves.